1. Field of the Invention
The disclosures herein generally relate to imaging devices and solid-state imaging devices.
2. Description of the Related Art
Solid-state imaging devices such as image sensors are broadly categorized into CCD and CMOS according to the type of imaging element. With respect to the arrangement of the imaging elements, the solid-state imaging devices are broadly categorized into area sensors and linear sensors. In an area sensor, imaging elements are arranged in a two-dimensional matrix. In a linear sensor, imaging elements are linearly arranged. In such solid-state imaging devices, various optical filters are used for enhancing the imaging functions.
The solid-state imaging devices are used for imaging monochrome or color images. In particular, a solid-state imaging device for color images is provided with a color filter serving as an optical filter, which allows transmission of light with specific wavelengths. The color filter is arranged on an optical path from an imaged object to the imaging element that receives the light. The provision of such a color filter makes color information of the imaged object available.
In a case where the color filter is arranged in the solid-state imaging device, primary color (i.e., RGB) filters or complementary color (i.e., CMYG) filters are provided above imaging elements provided on a semiconductor substrate. The color filters are provided by applying a light-sensitive resin containing a pigment or a dye above the imaging element in a producing process of the solid-state imaging device.
Uniformity is desired for optical filters such as color filters. For this purpose, when a material resin such as a light-sensitive resin is applied, a film forming method named a spin coating method is used as in the case where an interlayer insulating film or a photoresist used for patterning is formed.